fix(core): Use full path to env in functions.zsh

[ferdnyc]

Standards checklist:

• The PR title is descriptive.
• The PR doesn't replicate another PR which is already open.
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Changes:

• Replace bare 'env' with '/usr/bin/env', in uninstall_oh_my_zsh()

Other comments:

I have a shell alias for env, in my interactive shell environment. So, with just a bare env called in the uninstall_oh_my_zsh() function, re-executions of my .zshrc would report a parse error:

$ . ~/.zshrc                       
/.../lib/functions.zsh:8: parse error near `ZSH="$ZSH"'

It's safer to use /usr/bin/env there, same as in the various shebang lines for the executable scripts.

[ferdnyc]

Although it wasn't my intention in making this change, this PR may also help to address the issues encountered in the discussion at #11602.

However, to completely address that issue, it may also be advisable to unset the PATH envvar in the env command (/usr/bin/env -u PATH ZSH="$ZSH"), so that it will reset to the system default and allow sh "$ZSH/tools/uninstall.sh" to run successfully even if the $PATH was previously broken.

Thoughts on adding a -u PATH to the command?

[carlosala]

Thanks for your contribution!

[ferdnyc]

@carlosala

command env is a better solution for my case of having env aliased, agreed. But IIUC, it still won't help at all with situations like #11602 where (seemingly) the $PATH has been utterly corrupted, correct?

I wonder if there's still more that can be done to make the uninstall bulletproof no matter what state the system is in? (Just to give people a parachute for when they've broken something and can't figure out what / how to fix it.)